Activation of Cell-Specific Transcription by a Serine Phosphatase at the Site of Asymmetric Division

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Science  27 Oct 1995:
Vol. 270, Issue 5236, pp. 641-644
DOI: 10.1126/science.270.5236.641


Cell fate is determined by cell-specific activation of transcription factor σF after asymmetric division during sporulation by Bacillus subtilis. The activity of σF is governed by SpoIIAA, SpoIIAB, and SpoIIE, a membrane protein localized at the polar septum. SpoIIAB binds to and inhibits σF, and SpoIIAA inhibits SpoIIAB, which prevents SpoIIAB from binding to σF. SpoIIAB is also a serine kinase that inactivates SpoIIAA. Here, it is demonstrated that SpoIIE dephosphorylates SpoIIAA-P and overcomes SpoIIAB-mediated inhibition of σF. The finding that SpoIIE is a serine phosphatase links asymmetric division to the pathway governing cell-specific gene transcription.